Property account swallowed by lease (9)
I believe the answer is:
character
'property' is the definition.
(I know that character is a type of property)
'account swallowed by lease' is the wordplay.
'account' becomes 'ac' (abbreviation for account).
'swallowed by' means one lot of letters goes inside another.
'lease' becomes 'charter' (synonyms).
'ac' going inside 'charter' is 'CHARACTER'.
(Other definitions for character that I've seen before include "strength of mind" , "Personal moral qualities" , "Eccentric person" , "eccentric individual" , "I, for example" .)